Glossary of Terms

Glossary of Terms for the Scale Industry

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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Absolute Measurement
Absolute measurement uses measurement scales based on the fundamental units of a system. It relates to the condition at which a system contains none of the variables to be measured.

This is opposed to arbitrary scales that relate to a predefined numerical value. For example, when discussing temperature measurement, we use the Kelvin scale and the Celsius scale.

The Kelvin scale is absolute because it relates to the condition where a substance has no temperature, but the Celsius scale is arbitrary because its zero point relates to a predefined value of temperature (the melting point of water).

Absolute Pressure
Gage pressure plus atmospheric pressure.

Access
To read from and possibly write to area of memory.

Accuracy
The accuracy of a device or system is the extent to which any value it creates could be wrong, or the maximum error it may produce. With a sensor, it is how close the output value is to the actual value of the measurement. In practice, every device will produce an error, however small, and will have some degree of accuracy rating. It may be expressed in terms of the measurement units involved.

For example, suppose we have a thermometer with an accuracy of ±0.2°C. This means that if we take a temperature measurement with the thermometer and find it to be 20.1°C, then the actual temperature lies somewhere between 19.9°C and 20.3°C. Alternatively it may be expressed as a percentage error of the range of the device. 2) The combined error of non-linearity, repeatability, and hysteresis expressed as a percent of full scale output.

Accuracy / Precision
If the actual value is 4.321 and you say that it is 4.30, then you are precise to 3 places but inaccurate by .021. If a value is represented as a bull's-eye on a target, a group of guesses or measurements represented by closely grouped points have a high degree of precision.

If that group is near the center, it is highly accurate as well. On a bull's-eye, think of precision as how close to the center your arrow hits, and your measurement of precision as how closely you can group your shots.

Aeration
Interspersing of air or other gases with powders or particulate material causing reduction in density and consequent increase in flowability.

Aggregate
Dense clustering of particles into body or mass.

Agitator
Apparatus for shaking or stirring; device used to aid in flow of bulk material to condition material to constant density.

Alarm
Audible or visible signal that indicates abnormal or out-of-limits condition in plant or control system.

Algorithm
Set of procedures used for solving problem in finite number of steps.

Alphanumeric
A character set that contains both letters and digits.

Alphanumeric Display
Device capable of displaying characters (letters, numbers, and symbols) but not graphics.

Ambient Conditions
The conditions (humidity, pressure, temperature, etc.) of the medium surrounding the device.

Ambient Temperature
Temperature of medium (air, water, earth) into which heat of device is dissipated. Note: 1) For devices that do not generate heat, this temperature is same as temperature of medium at device location when device is not present. 2) For devices that do generate heat, this temperature is temperature of medium surrounding device when it is present and dissipating heat. 3) Allowable ambient temperature limits are based on assumption that device in question is not exposed to significant radiant energy sources.

Analog
Representation of numerical quantities by means of physical variables such as voltage, current, resistance, rotation, etc. Contrast with digital.

Analog Backup
Alternate method of process control by conventional analog instrumentation in event of failure in computer system.

Analog Gage
Measuring device that indicates measurement result via analog signal. Contrast with digital gage.

Analog-to-Digital Conversion (A/D conversion)
Production of digital value whose magnitude is proportional to instantaneous magnitude of analog signal.

Angular Load, Concentric
A load applied concentric with the primary axis at the point of application and at some angle with respect to the primary axis.

Angular Load, Eccentric
A load applied eccentric with the primary axis at the point of application and at some angle with respect to the primary axis.

ANSI
American National Standards Institute: organization that develops and publishes voluntary industry standards in U.S.

Arching
Where deaerated or agglomerated process material forms in arch-like barriers above bin or hopper discharge, preventing further flow.

ASCII
American Standard Code for Information Interchange. Eight-level code intended to provide information code compatibility between digital devices. This information code normally represents alphanumerics, punctuation marks, and control-code characters.

Aspect Ratio
Ratio of the height to the width on a storage vessel.

Asynchronous
Recurrences or repeated operations that take place in patterns unrelated over time.

Attribute
Means of characterizing data on display device (e.g. intensifying, blinking).

Auger
Helical or closed flight screw-like device used to move or control material.

Auto Zero
An automatic internal correction for offsets and/or drift at zero voltage input.

Auto Shut-Off
Most battery powered digital scales will offer auto shut off to extend battery life. Some scales offer programmable auto shut off (i.e. 1 minute, 2 minutes, etc.)

Average
Numerical results obtained by dividing sum of two or more quantities by number of quantities; arithmetical mean. Example: Average of 7, 9, 17 is (7+9+17=33 ÷ 3) or 11.

Average Piece Weight (APW)
On a counting scale, the amount of weight divided by the number of samples which comprise that weight. APW is used by the counting scale to count pieces during normal operation.

Axial Load
A load applied along or parallel to and concentric with the primary axis.

Axis
Principal direction along which movement of tool or work piece occurs.